As the number of telephone calls seeking emergency assistance increases in a given region, some problems have surfaced. A caller seeking emergency assistance (referred to as an "EA caller" for convenient reference) is often under great stress and may not be able to give an accurate description of the location of the emergency site. The emergency service call operator who receives such a call may be unfamiliar with the locations of each emergency assistance service ("EAS") agency that can properly respond to the call and may be unable to determine which of these agencies is available and can respond most quickly to that location. Recently, in a Northern California community, a car overturned and caught fire, trapping the driver inside. A passerby immediately called "911", reported the accident, and requested immediate dispatch of a fire engine and crew to put out the fire and administer first aid and emergency services to the trapped driver. The 911 service operator called a fire engine crew on the other side of town, not realizing that the closest available fire engine crew was less than two miles from the accident scene along a low-traffic road. When the summoned fire engine crew arrived 15 minutes later, in part because the location of the accident scene was wrongly reported, the driver had perished from the flames, not from any injuries sustained in the accident itself. An approach is needed that removes the factor of EAS operator ignorance in prompt response to a 911 call for emergency assistance.
Another problem is manifested where, in response to an EA call requiring at most one responder, two, three or more EAS responders arrive at an emergency site in response to the call. Another problem arises in lack of means for monitoring whether the assigned EAS responder has, in fact, arrived at the emergency site and whether additional assistance and/or equipment is needed at that site.
Workers in the field of EA response systems have from time to time proposed systems that address some, but not all, of these problems.
In U.S. Pat. No. 3,864,522, DeKozan et al disclose a system for automatically determining the location of a telephone used to make a call to an emergency station (ES). When the ES receives a phone call, the ES telephone transmits a low frequency interrogation signal (at about 1 kHz), requesting the location of the caller's phone. This interrogation signal is answered by a response, using a binary or two-tone sequence of pulses indicating the location of the caller's phone. This response signal is received and decoded, and the caller's phone location is stored for subsequent use for an emergency response. This system requires two-way response: transmission of an interrogation signal, and transmission in the reverse direction of a response signal. The caller's phone location must be unchanging so that a static location can be stored thereat, for response to an interrogation signal. The person responding to the emergency call must then rely on his or her personal knowledge to dispatch the correct responder to answer the emergency call.
A security alarm system for detecting and signalling the presence of abnormal or emergency conditions in a specified area is disclosed by Wadhwani et al in U.S. Pat. No. 3,925,763. The system relies on placement of sensors that respond to the occurrence of specific events. When such an event does occur, a coded signal, including the location and event type that has occurred, is sent along a telephone or other signal-carrying line to a central station, where the signal is decoded and an appropriate response is determined. The system also includes circuitry that interrogates the sensors and lines to determine whether any component of the system is not operational.
Tuttle et al, in U.S. Pat. No. 4,176,254, disclose a roadside telephone system for emergency calls to a central station to obtain emergency assistance. Each roadside telephone module includes a handset, transmitter, receiver, and a sequence of switches or buttons that request a response by a particular type of emergency responder, such as fire truck, police, ambulance or auto road service. The phone handset or these switches may be used to inform the central station of the type of emergency, but the caller must use the handset to verbally inform the central station of the caller's location--assuming that the caller knows the location. A timing circuit automatically disconnects the phone connection after three minutes if the handset is still off-hook, to conserve electrical power.
U.S. Pat. No. 4,237,244, issued to Moore, discloses a rapid response communications system for use in a hospital or other large health care facility. The system includes personal locators, to be used by specified health care personnel, such as doctors, nurses, interns, orderlies, etc. in the facility. When a health care person enters a room, that person presses a button whenever that person enters a room at the facility, using a panel of buttons beside the entrance to the room. This panel includes one button for each type of health care personnel: doctor, registered nurse, practical nurse, technician, aide, emergency responder. Pressing a panel button causes a central display, located on one or more floors of the facility, to indicate that a health care person of that type has entered that room. When the health care person leaves the room, that person presses the same button or takes some other action to indicate that that person has left that room, for purposes of the central display. It is unclear what action is taken to indicate that, say, more than one doctor is present in a given room or that one of these doctors has just left the room. When a patient or other person needs the assistance of a particular type of health care person, the patient contacts the central station, which locates an available health care person using the information shown on the central display.
Ray et al disclose an automatic emergency caller locator system in U.S. Pat. No. 4,878,236. The system, which is apparently intended to be part of a roadside telephone module, senses when a phone call is being placed to a 911 number and turns on a flashing light or strobe to allow an emergency responder to more easily locate the caller. An authorized person resets the telephone module and deactivates the light, for example by dialing a predetermined phone number. This system relies upon the caller to verbally state an approximately correct location for the emergency responder. A similar system, which turns on an exterior visual or audible alarm that can be easily sensed when a 911 call is made from a house or other building, is disclosed in U.S. Pat. No. 4,931,780, issued to LaMont et al, and in U.S. Pat. No. 5,012,507, issued to Leighton et al.
A personal locator for emergency situations, to be worn by a child or other person to be located, is disclosed by Lawrence in U.S. Pat. No. 5,021,794. The locator responds to receipt of a selected locator signal, such as a particular frequency or combination of frequencies, by transmitting a characteristic UHF response signal that can be located by one or more tracking vehicles, using signal triangulation. A parent or other person who needs to locate the person wearing this locator device transmits a selected digital pulse code over a telephone line, and a non-directional UHF locator signal is transmitted to cause a response signal to be transmitted by the locator device. A tracking vehicle can be given additional information, such as general appearance, gender, age, etc., concerning the person to be located, by radiowave signals.
In U.S. Pat. No. 5,077,788, Cook et al disclose a system for processing calls for emergency assistance, in which the telephone number of the phone caller is automatically identified and used to retrieve information stored in a database. The caller is patched through to the appropriate emergency response agency, and relevant information in the database (e.g., address of the calling station, structure in which the calling station is located, if any) is forwarded to that agency for use in responding to the call for assistance. Optional validation of the caller's phone number is available, for use in screening such calls.
Enhancement of an emergency response system is disclosed in U.S. Pat. No. 5,091,930, issued to Shapiro. This system incorporates an ancillary radiowave subsystem as an alternate communication link between the caller for emergency assistance and the emergency response central station. This subsystem is used to detect whether telephone line interference is present and to provide the caller with an alternative means of communicating with the central station.
Thompson, in U.S. Pat. No. 5,109,399, discloses a computer-based emergency response system in which, upon receipt of a call for emergency assistance at a central station, a map is automatically displayed showing the caller's location at the same time that the voice message is being received. The voice information and/or map information can optionally be communicated to an emergency responder agency, for use in responding to the call. This system does not determine availability of a responder agency or provide an estimate of the time required for response. Location of the caller must be provided by the caller or by identification of the number for a telephone at a fixed location.
A call interceptor for emergency assistance calls that identifies the phone number of location of the source of the call is disclosed by Chavous in U.S. Pat. No. 5,161,180. When a 911 number is dialed from a phone that is part of the network, a subsidiary device interrogates the caller's phone, obtains the phone number, searches a database on phone numbers, and provides the telephone phone number and location of the caller's phone to an emergency response central station. If a response to the interrogation signal is not received, the system uses an alternate route to interrogate the caller's phone.
In U.S. Pat. No. 5,218,367, Sheffer et al disclose a vehicle tracking system that uses a conventional cellular telephone network to report the occurrence of an emergency or of certain other kinds of abnormal events. Special purpose sensors placed on the vehicle sense the occurrence of a specified class of "events" and transmit an emergency message, without human intervention, over the cellular phone, which is preferably concealed on the vehicle. The message transmitted can include information on the type of emergency or abnormal event, vehicle identification, cellular phone zone, and signal strength information. No information directly identifying the vehicle location is included.
U.S. Pat. No. 5,305,370, issued to Kearns et al, discloses a handheld transmitter that enhances use of an emergency assistance system. If a person in need of emergency assistance cannot reach a telephone, this person uses the handheld unit to activate a base unit nearby that places the call and provides two-way voice communication between the caller and an emergency response central station. The base unit would normally be located in the caller's home or place of business and could be used by a person who is injured, disabled or otherwise unable to physically move to and use a conventional telephone. This device can also be used to transmit a silent alarm if a robbery or other similar event is taking place.
Brozovich et al, in U.S. Pat. No. 5,311,569, discloses a phone line-based emergency assistance system that can obtain information on a phone used to make a 911 call, even if the caller is subsequently unable to respond. This includes provision of Automatic Number Identification (ANI) for, and the address of, the caller phone, along with other information contained in a database, such as the building and/or floor and/or section of the floor where the caller phone is located. The information is then optionally displayed at an emergency response central station.
These inventions provide means for obtaining information on the EA caller's location for a limited class of telephones, such those that have a fixed location that can be entered in a static database or those that belong to a special network. What is needed is a system that provides location information for any telephone, mobile or fixed-location.
Also needed is a system that provides means for subsequently monitoring the EAS responders actions, such as arrival at the emergency site, and means for assigning one or more additional EAS responders in light of subsequent developments.